Air-driven motor control



sept. 23, 1930.

AIR DRIVEN MOTOR CCNTROL Filed Feb. 19, 1927 R. H.' RANGER 1,776,372

RlCHARD HOWLAND RANGER mkg/4 @am Patented Sept. 23, 1930 UNITED STATES PATENT OFFICE RICHARD HOWLAND RANGER, OF NEWARK, NEW JERSEY, ASSIGNOR T0 RADIO COR- PORATION OF AMERICA, A CORPORATION OF DELAWARE AIR-DRIVEN MOTOR CONTROL Application .filed February 19, 1927. Serial No. 169,620.

My invention relates broadly to the method of and the apparatus for controlling motors by means of an air driven tuning fork or other constant vibrating system. More spe cifically my invention relates to a tuning fork motor control wherein the tuning fork is made of quartz and has a relatively low vibrational frequency, which is preferably below the audibility range.

Heretofore, it has been difiicult to drive quartz tuning forks, since it was necessary to add pieces of steel to the forks, and this addition, it was observed, had a more or less detrimental effect on the accuracy of the fork itself.

The device which is herein described has used an air means for driving the fork, and at the same time further utilizes the air to control the motor through a brake means to be hereinafter described.

An object of my invention is, therefore, to

produce a novel means for controlling a tuning fork by means of an air jet.

A further object of my invention is to produce a method and means for utilizing an air jet or a certain air pressure to control motor speeds.

Still a further object of my invention is to provide a means for controlling a motor and a tuning fork without the use of electrical apparatus, and thus prevent the causes of considerable interference in both radio and audio amplifying circuits, due, for example, to vibrating contacts and brushes.

Still a further object of my invention is to devise a system of motor control that is equal- 1y applicable to direct and alternating current motors.

Still another object of my invention is to provide a means for controlling motor speed by means of a vibrator of a constant period.

Still another object of my invention is to provide a regulating or control system which will start to operate as soon as the air is turned on, Without any need for striking the fork to start it.

Still other objects of my invention are to provide in a manner hereinafter set forth, an air driven tuning fork motor control system which is relatively simple in its construction and arrangement of parts, as well as a system which is durable, compact, efficient in its use, conveniently operated, readily set up, foolproof, and relatively'inexpeiisive to install.

The novel features which I believe to be characteristic of my invention are set forth in the appended claims, the invention itself, however, both as to its organization and method of operation together with further objects and advantages thereof, will be best understood by making reference to the following specification when read in connect-ion with the accompanying drawings; wherein:

Fig, 1 is a perspective plan view showing the general arrangement of elements;

Fig. 2 is a view showing the valve operating cam together with the bellows operated brake means; and,

Fig. 3 is a schematic view illustrating the air vibrating means for the tuning fork.

Making reference now to the above identil fied drawings which form a part of my disclosure, air from any desired source of constant pressure (not shown) is carried through an air hose l to an air chamber 2. Leading in to the air chamber 2 is a small inlet hole 3 ada ted topermit the inward passage of air. ranching ofl" from either side of the air chamber at points 90 from the inlet 3 are two larger openings 4 and 5 which open toward a tuning fork, generally designated 6. Placed against each of the openings 4 and 5 and flush with them are a pair of cylindrical plugs 7 which have their opposite end 8 iattened and attached to the end of the tuning fork 6 by means of a screw or some other equivalent means or may be, if preferred, cast directly as part of the fork itself. Leading out from the other end of the air chamber, that is, the end directly opposite the point of air entrance 3 is a fourth opening or duct 9 leading to a tube 10 which I will hereinafter describe as an air resonant column.

The tuning fork is mounted above a base member 11 of any preferred form which supports a clamping means 12 in which the end 13 of the fork 6 is clamped. The tines 14C of the fork extend outwardly from ythis clamping means toward the air chamber 2 to the point where the tines are fastened to the plugs 'i' which, as above described, rest against the air chamber and through-the openings of which air passes out to drive the forlrin a manner to be hereinafter described. At various points between the clampv means 12 and the ends of the fork tines are guiding members 1.5 in which the tines of the fork are adapted to rest and move.

l will now endeavor to describe the method of vibrating the fork by means of the air supply. lt has been found that the tuning fork, through the attached plugs 7, acts as a baa on the outlets fl and 5 from the air chamber 2, and that as air fills the air chamber it gradually forces the plugs outwardly in a manner that will in turn force the tine outwardly. Upon the outward movement of the fork tines the plugs 7 are moved a slight amount away from the air chamber and the air pressure released. After the tine has been forced outwardly it tends to return to its original position and in doing so brings the plug back to its former position against the v outlet from the air chamberso as to again charge the chamber with air. lt may, therefore, be seen that there is an alternate charging and discharging action of the air taking place in the chamber which takes place according to the period of vibration of the forl. This action gives a good clean cut vibration to the fork, and by the method herein described it is possible to have an exceedingly low intensity of vibration to the fork, and, naturally, the lower the vibration intensity, the more constant the period of the fork. By means of the air it is possible to work with a much less intensity of vibration than is normally possible with an electric driven tuning fork, and it may also be seen that the rate with which the air is permitted to ill the air chamber is made the same as lthe period of the fork, which in itself means accuracy. Under the above described conditions the air which is led to the air chamber is under constant pressure, and when the air chamber is broadly resilient to the period of the tuning fork there is little or no dificulty in sustaining vibration of the fork with very low air pressure.

'lo now continue with the description of the apparatus, at a point about mid-way of the length ofthe tuning fork G is a pair of supporting brackets 15 mounted on either side of the fork. Supports 15 are connected arrastra together at their top by means of a strip 16 of metal or other suitable material, to the mid-point of which is secured, in any preferred manner, a bracket arm 17 adapted to support an air valve 18. Valve 18, although not shown in detail by the drawing, is preferably of a type that consists of a seat upon which a slidable valve rod rests in much the same manner as the well known lll slide valve. The valve rod is formed from a rod of any preferred form which is drawn to a slightly less diameter at one point in its length so that a movement of the valve rod over the valve seat to the point of lesser diameter will permit the flow of air therearound. Leading into the valve 18 is a connection 19 to the resonant air column 10 at a point near the end of the said column, and leading out from the valve 18 above the valve seat is a connection 20 to which a second air hose 21 is attached.

'lhe air hose 21 is carried to a bellows member 82 which is placed upon the supporting base 11 and is adapted to be supplied with air at each opening of the valve member 18. Further description of the function of the air supply to the bellows member will be hereinafter set forth in connection with the complete operation of my device.

A motor 22, which may be of a direct or alternating current type, is mounted a short distance from the fork 6 upon the base 11. Upon the shaft 23 of the motor is placed thev usual fly-wheel 24 to assure stability of oper ation and to roughly maintain constant speed.

rlhe shaft 23 is extended beyond the dy-wheel, and upon the shaft as extended is placed a cam member 25, which l will hereinafter de scribe in connection with the operation of the valve 18.

Associated with the cam member 25 is a roller 27 mounted upon an arm 28 pivoted at 28a to the base member 11. At the upper portion of the arm or lever 28 is secured a rod 29 which is attached to the stem or rod above described in connection with the valve 18. The valve rod 29 is pivoted upon the lever or rod 28 at 29LL in a manner to permit an up and down movement and is carried to the stem of the valve over a grooved wheel or i pulley 30 which serves as both a guide and mid-point support.

' For the purpose of keeping the cam roller 27 at all times against the cam, a spring (or any other preferred means) may be employed. For the purposesof illustrating, l have connected one end of a spring 81 to the pivoted rod 28 and fastened the free end of the said spring to the framework support 89. 'lhe sole purpose of the spring, which may be of any desired and appropriate type, is to keep the roller always against the cam.

lt may thus be seen that with the cam 25 rotating once for each revolution of the motor shaft that by the nature of the attach- Mtl ment of the valve rod to the lever carrying the cam roller, that for each rotation of the motor shaft the valve rod is moved back and forth once. As above described, each reciprocation of the valve rod will open and close the valve 18 by means of the D slide therein contained and permit a passage of air into the air hose 2l which leads to the bellows members 32. The preferred type of bellows is closely similar to those now known to be used on the usual type of player pianos.

A rod 33 is fastened to the outer end of the bellows and is adapted to be moved up and down as air is permitted to flow into the bellows so as to expand the same. Attached to the upper end of the rod 33 is a second rod or lever 34 which is pivoted at a point 35 somewhat near its center to a support 39 which also carries the roller 30 upon which the valve rod slides. The other end of lever 34 is fastened to the free end y36 of the brake band 37 which is extended around theV fly wheel 24 and has its other end fixedly secured to the framework or support 39 at a point 38.

Upon the bellows is a small air valve 40 which is adapted to permit air to gradually leak out and thus relieve the pressure upon the bellows. i

Although I have previously described certain parts of the operation of my invention in connection with the description of the separate elements, I will now describe very briefly the complete operation. The air entering from the constant pressure source into the air chamber forces the plugs which block the openings to move outwardly which causes the fork tines to be likewise moved. This then relieves the contained air pressure very quickly, after which the .fork tines spring back. Upon the forced inward movement of the fork after being pressed outwardly by the air, a pressure is again built up in the air chamber and air is caused to pass through the opening 9 into the resonant air column, and to be directed toward the air valve 18.

As has been seen from the first part of my description, the air valve is opened and closed at each rotation of the motor shaft and, therefore, upon each opening of the valve, air is permitted to flow'into the bellows.

The amount 'of air which is let out from the resonant air chamber into the bellows is a question of the pressure which exists at that particular moment. If it is a high pressure, a large quantity of air will flow out, and if it is a lower pressure, less air will naturally flow. It is, therefore, a question of the relative phase of the valve opening with respect to the air pressure. As the air pressure changes through the action of the tuning fork, the quantity of air is then really determined by the tuning fork. The motor will settle into a running position such that the valve will be opened at a phase angle with respect to the fork vibration, to allow sufficient air to enter the 'bellows to hold the speed just Y behind the phase of the fork where more air would be passed. There is enough leeway in this automatic phase adjustment to take care of considerable variations in load and conversely variations in torque of the motor due to applied line voltage variations.

The small valve 40 holds the air pulses in the bellows suiciently to make an even pres` sure on the brake; and at the same time a1- lows enough to escape to make the system responsive to changes. The movement of the rod 33 caused by pressure in the bellows controls the amount of movement of the lever 34, that is, pressure applied to the brake band and thus on the motor. Upon the motor and the fork reaching the proper and predetermined phase relationship, the pressure in the bellows will become steady .and the braking effect will be such as to keep the motor at just the right speed. It may readily be seen from the above that -I have provided a scheme inwhich air is the exclusive means of motor control and that, in the absence of any electrical contacts, the causes of considerable electrical interferences is avoided.

Having thus described my invention, I am entitled to all modifications thereof that lfairly fall within its spirit and scope, as defined by the following claims, wherein I claim:

1. In a motor speed regulator system, a tuning fork, an air-drive for said fork, a motor, and means operable at the period of said fork for regulating the speed of said motor.

2. In a motor speed regulator system, a tuning fork, means for driving said fork, a motor, and means operable from said driving means for said fork for regulating the speed of said motor.

3. In a motor speed regulator system, tuning fork, a motor adapted to be controlled at each vibration of said fork, land an air means adapted to vibrate said fork and control said motor speed.

4. In a motor speed regulation system, a motor, and a constant period vibrating device associated therewith for controlling the speed of said motor.

5. In a lmotor speed regulation s vstem, a motor, a tuning fork, an air supply or driving said tunin fork, and means associated with said tuning fork for controlling the .speed of said motor, said last named means being operable from the said air used for driving the' said tuning fork.

6. In a motor speed regulation system, a motor, a speed reducing means associated therewith, a constant period vibrator associated with said motor and speed reducing means, and means for causing said vibrator to react upon said speed reducing means to control the speed of said motor.

l. ln a motor speed regulation system, a motor, a speed reducing means associated therewith, and vibrating means adapted to actuate said speed reducing means at delinite predetermined intervals.

8. lln a motor speed regulation system, a motor, a tuning fork, a brake associated with motor, and air means for driving said 'forli and applying a pressure at the period oli said fork to said brake, whereby tbe motor speed may be regulated.

lin a motor speed regulation system, a motor, a constant period vibrating device, a brake associated with vsaid motor, and means operable at the period o said vibrating device `for applying a pressure on said brake ait-predetermined intervals in accordance with any relative variance between the motor speed and the period ot said vibrating device.

1G. ln a motor speed regulation system, a motor, a tuning fork, a resonant air column associated therewith, air means for driving said -loria, and means operable at the period of said fork for forcing air into said column, a brake means connected with said motor, and means connected with said air column 'for controlling pressure on said brake means in accordance with 'the air pulses in said air column.

lljln a motor speed regulation system.

a motor, a tuning fork, air means for vibrating said fork, an air column, means to permit an air pressure to build up in said air column at the period of said fork, valve means associated With said air column for directing' the said air, means operable from said motor for regulating the period ol" opening and closing ol said valve, and means operable by tbe air flowing through the said valve for maintaining the speed of said motor at a constant value.

l2. lln a motor speed regulation system, a motor, a Wheel upon the shalt of said motor, a brake-'band about said Wheel, a tuning turk, and air driven means tor regulating the tension on said brake-band upon any relative change between the speed ot said motor and the vibrational 'frequency oll said tuning forli.

lil. A tuning fork, air means for driving said forli, a motor, and means operable from tbe air driving said tuning 'forli for regulating speed oit said motor.

lln a motor speed regulation system, a motor, a brake associated with said motor, a tuning forli, means for driving said tuning for t, a valve associated with said fork, means :tor supplying air to said valve at the period of said iiorlr vibration, cam and lever means tor opening and closing said valve in accordance 'with tbe rotational speed oi said motor, and means operable from the air passing tnrougli said 'valve at eacla opening for regutlie pressure on loa'wliereby l agradar tbe motor speed is controlled in proportion to the relative deviation of motor speed from the constant vibrational frequency of said tuning fork.

l5. ln a motor speed regulation system, a motor, a brake associated therewith, a tuning fork, air-driven means for vibrating said fork, an air column associated with said vibrating means, means 'for building up an air pressure in said column at the 'frequency of said fork vibration, an air valve connected with said column, means driven from said motor for opening and closing said valve by the rotation of the motor, a bellows, and a. connection means connecting said brake and said bellows, and a connection between said bellows and said air valve, said connection serving to supply an air pressure to said bellows whereby the bralre tension on said motor is regulated in proportion. to the relative deviation oi the rate of valve opening to t'ne constant vibrational frequency of said tuning fork.

1G. ln motor speed regulation system, a motor, a tuning fork, means for vibrating said tuning fork, a bellows, means tor inducing an air pressure in said bellows, said air pressure being proportional to the relative deviation ori speed in sm'd motor trom tbe vibrational frequency off said tuning t'ork, and means operable from said bellows 'for bringing tbe speed of said motor into a synchronous relationship Witli tbe frequency of said tuning fork.

l?. ln e, motor speed regulationsystem, a motor, an air-driven tuning Jfork, a bellows mechanism, means for supplying an air pressure to said bellows, said means being operable each rotation of said motor and said pressure being regulated by the relative time of operation oit said means and tbe vibrational period ot said fork, and means operable from tbe pressure ivitbin said bellows iior supplying a controlling effect on tbe speed ot said motor.

18. ln combination, a motor, a bralre and a tuning fork, and means so connecting said tuning *forli and said brake that said brake is applied to said motor at periods corresponding to the periods ot deviation oic said motor speed from the constant period or' said tuning liorlr.

19. ln combination, a motor, a brake connected with said motor, a tuning fork, an air drive for said tunin fork, and means opn erable at periods of eviation of said motor speed from the constant period vibration of the said tuning fork for supplying the air utilized in driving said fork to said brake for exerting a correct-ive force upon the speed of said motor.

20. ln combination. a motor, a brake, a tuning fork, an air drive for vibrating said Jfork at the natural period thereof, and means operable during periods of deviation of molll@ tor speed from the vibrational period of said fork for applying a braking force upon said brake for correcting the speed of said motor. 2l. In combination, a motor, a brake, and

5 a mechanical vibratory system having a natural period substantially corresponding to the period of rotation of said motor, an air drive means for vibrating said mechanical vibratory system, and means operable lo during periods of deviation of motor speed from the natural period of vibration of said vibratory system for applying a correcting braking force upon said brake member.

RICHARD HOWLAND RANGER.

D l SG L Al M E R 1,776,372-i-Richard Howland Ranger, Newark, J. AIR-DRIVEN MOTOR CONTROL. Patent dated September 23, 1930. D1sela1mer` filed November 2S, 1930, by the patentee, assignee, Radio Corporation of Amerzca, assentmg. Hereby enters this disolaimerto claim 4 in the said specification Which is in the following Words, to wit: n a

In a motor speed regulation system, a motor and a e'onstant period Vlbratlng device assooiated therewith for controlling the speedof sald motor.

v [Oficial Gazette December 16, 1.930.]

DISOLAHVIER 1,776,37 2.-R'ichard Howland Raf/iger, Newark, J. AIR-DRIVEN MOTOR CONTROL. Patent dated September 23, 1930. Disclaimer filed November 28, 1930, by Jche patentee, assignee, Radio Corpomtion of America, assenting.

Hereby enters this disclaimer to claim 4 in the said specification which is in the following Words, to Wit:

In a motor speed regulation system, a motor and a constant period vibrating de Vice associated therewith for controlling the speed of said motor.

[Ocial Gazette Decembe?q 16', 1930.] 

